What makes Iowa Speedway so challenging for IndyCars

The sub-one-mile Iowa Speedway offers a unique challenge in the context of the other races on the IndyCar calendar, but what makes it even more demanding is its own evolution, as race engineer Ray Gosselin explains.

One of the most enjoyable aspects of IndyCar’s track diversity is that within 10 days of the checkered flag falling at one of the world’s great road courses, four-mile Road America, we can watch the same cars average 180mph around a 0.894-mile oval.

It’s every bit as stark a contrast as the switch from Indianapolis Motor Speedway to Belle Isle, Detroit.

The Iowa Corn 300 is also one of the most enjoyable events on the schedule. No, I don’t like the fact that NBC’s relationship with NASCAR has forced IndyCar to move from Saturday evenings to Sunday afternoons, but aside from that, no complaints.

Like the GP of Long Beach, Iowa Speedway attracts fans of both kinds – those who know the series inside out, and those who attend because it’s a fun annual event – and Iowa’s staff members are also helpful and welcoming.

But most importantly, the track is unique. The front ‘straight’ is not only curved, it also has 10 degrees of banking. Then as the cars hit Turns 1-2 they tip further over, to 14 degrees, before catapulting along a near-flat back straight (which is genuinely straight).

And all the way around and across all lanes, the track is bumpy. Go stand on the inside or outside of the turns and watch IndyCars try and soak up the uneven surface at 170-plus mph and you know you could be nowhere else.

Yup, Iowa Speedway is one of those rare ovals on which an IndyCar can provide a true spectacle even while running alone; get a couple of dozen of them together and entertainment is guaranteed.

The team that has dominated the track’s 11 years on the IndyCar calendar is Andretti Autosport. Seven times, one of Michael Andretti’s drivers has stood on the top step of the podium, and it’s remarkable that this run of success has spread across the ‘old’ Dallara IR03, the original spec DW12, and the DW12 with manufacturer aerokit.

Judging by the team’s 1-2-3-4 in the 13-car test last week, this weekend the team’s Iowa victory tally may well reach eight, and across four very different aero packages.

Yet Gosselin, who has race engineered Ryan Hunter-Reay to all three of his Iowa wins, says that the most noteworthy factor in the team’s run of success has been the fact that they’ve kept up with the natural maturation of the track.

He tells Motorsport.com: “The thing that gets lost in discussions about the new cars – whether it’s switching from the IR03 to DW12 in 2012, manufacturer aerokits in 2015, and now this new spec aerokit – is how much the track itself has evolved dramatically from when we first went there in 2007.

“Back then we had fresh paving and it raced like, say, Texas Motor Speedway in the IRL era – two by two, side-by-side, five rows deep, and where you qualified was pretty much where you were going to finish, barring a pitstop problem.

"In qualifying it was all about managing track distance, so you’d have to come to a compromise between what trim you could run versus what line you could take – fairly similar to any 1.5-mile oval from that era.

“But Iowa became more challenging pretty quickly and even by the end of the IR03 days in 2011, it had become tougher as the surface wore in.

"It’s become a lot bumpier over the years. Initially we had that one massive bump just after the tunnel to the infield, but now there are bumps all over the place because winters aren’t particularly kind there.

“That’s what happens with age. Texas has become a very smooth and high-grip surface since the repave before last year’s race, but five years from now, it will be a different story. It’ll pick up bumps and imperfections.

"And that’s precisely what’s happened at Iowa – its surface is 12 years old, and yeah, that big bump is still there but it’s acquired a lot of friends now, and they’re all waiting to catch you!”

Point taken – Andretti Autosport’s ability to keep up with the track’s evolution is noteworthy. But so long as the test didn’t steer us wrong, the team has also adapted amazingly well to the 2018 spec aerokit which, as we know, robs the IndyCars of top-surface-produced downforce from previous years and transfers much of its downforce generation to the underside.

Last summer, both of IndyCar’s testers of the new kit – Juan Pablo Montoya [Chevrolet] and Oriol Servia [Honda] – advised the series to run the lower of the two downforce setups they tried at Iowa. Having a differential of 20mph between terminal speed and turn speed, they said, would promote racing and make the cars more demanding.

IndyCar listened to this logic and, according to Gosselin, the difference between maximum and minimum speeds will become even more noticeable than that.

“The manufacturer aerokit cars were very high on downforce but also more draggy,” he says. “In fact, the last three years we were slower in terms of top speed than we had been in the first three years of the spec DW12.

“With this 2018 kit, top speeds on the straights are 6-8mph higher than last year, despite us coming off the turns slower. That’s impressive because the straights are so short at Iowa that the speed in the previous corner has a massive impact on your straightline speed and we’re now going 12-15mph slower than last year in the turns!

“So last year on a clear lap we’d do 180-182mph on the straights, but only drop to 172 in the turns; we were barely accelerating. This year, on a perfect lap on new tires, you’re going to see us doing around 189 on the straights but back off to around 165-ish in turns.”

More startling still, says Gosselin, will be the loss of speed in traffic come raceday.

“In that respect, it’s going to be very similar to a traditional short oval,” he says. “We’re always lifting off the throttle in the turns, but in traffic there’s going to be a huge difference – almost like how it was at Milwaukee, where you lose a lot of mid-corner speed behind slower cars. I’m sure you’ll see some laps where the leaders are slowing down 30-40mph while navigating traffic.

“Right now, we don’t know how this car is going to race; without having a full field out there during the test, it’s hard to tell. But as a general rule on these shorter ovals, the racing really starts when the leaders catch up with the backmarkers, and one guy will be quicker at getting through traffic than the guy he’s racing.”

With the reduction in downforce comes more lateral movement. Marco Andretti told Motorsport.com earlier this week: “The car’s really light on downforce compared with previous years… The rear felt like it was just skimming from bump to bump and never really felt ‘in’ the track.”

All that sliding across a coarse surface means tire degradation in this weekend’s race could increase dramatically over previous years, thereby producing another equation with which engineers and drivers must conjure some magic.

Iowa’s short lap means track position is theoretically key, therefore minimizing the number of pitstops is highly desirable, but the increased tire deg can stymie that plan. Is it true, I ask Gosselin, that stint length could be as much as 85 laps?

“It might be even more than that, once you get into the race and the pace starts slowing down a little,” he replies. “In high tire-deg races, you start slowing down, and then you get traffic and the pace slows down even more.

"The drivers are yelling for fresh tires but you can’t stop because the penalty of doing an extra stop is massive at such a short track. Under green-flag conditions at Iowa, you can lose two-and-a-half to three laps by pitting, so you have to keep soldiering on. But yeah, 85-90 laps could be a stint length under green….”

One of Iowa’s pleasing characteristics that is set to continue despite high tire degradation and a 300-lap race is that marble build-up should not impinge too much on how much room there is to race.

“More track width is used there,” says Gosselin. “The passes don’t happen going into the corner and then the drivers go down to single-file. That’s what Milwaukee was like.

"At Iowa the straights are too short to pass before the corner, so the passes actually happen in the corner – someone on the inside, someone on the outside. So the marbles situation is almost self-policing.”

Between that and the greater challenges faced by drivers and their race engineers, this weekend’s Iowa Corn 300 promises to be another sparkling event in the track’s history. Just a couple of weeks after the Phoenix race was canned, it seems particularly important to keep IndyCar’s short-oval tradition alive.

“I hope it’s a good race because we can put on good races at Iowa,” says Gosselin, “and it attracts a decent crowd and the crowd there is very into their sport. They’re very appreciative, respectful and knowledgeable. We want to keep them coming back.”